Claims
- 1. A display controller for use with a scanning-type display device for providing a plurality of display dots on a screen thereof and a memory for storing a plurality of display data, each corresponding to a respective one of the display dots to determine a color thereof, said display controller reading each of said plurality of display data in synchronization with the scanning of the screen, forming a display signal in accordance with the read display data, and supplying the display signal to the display device to thereby display an image on the screen, said display controller comprising:
- first pattern memory means for storing a group of bits representative of a first pattern of a cursor on a screen as a dot matrix;
- reading means for reading said group of bit from said first pattern memory means at a timing such that said first pattern will be displayed on the screen at a selected position thereof, to form a first pattern timing signal;
- first register means for storing first data representative of a first color;
- first logical operation means, responsive to said first pattern timing signal, for changing a color of a first portion of said display data stored in said first pattern memory means corresponding to said first pattern, to a changed color by effecting a first logical operation between said first data and said display data to output a modified display data;
- second pattern memory means for storing a second group of bits representative of a second pattern of said cursor as a dot-matrix;
- said reading means including means for reading said second group of bits representative of said second pattern from said second pattern memory means at a timing such that said second pattern will be superimposed upon said first pattern displayed on the screen to form a second pattern timing signal;
- second register means for storing second data representative of a second color;
- second logical operation means, responsive to said second pattern timing signal, for changing a color of a second portion of said display data which corresponds to said second pattern, which is within said first pattern from said color to another color, by effecting a second logical operation between said second data and said first operation result outputted from said first logical operation means, to output further modified display data; and
- display signal forming means for forming the display signal in accordance with said further modified display data.
- 2. A display controller according to claim 1, wherein said first logical operation means includes means for selectively performing a logical operation based on first operation data applied thereto, and further comprising third register means coupled to said performing means, for storing said first operation data to determine a specific logical operation performed in said first logical operation, so that said first logical operation means effects said specific logical operation commanded by said first operation data.
- 3. A display controller according to claim 2, wherein said first logical operation is a logical multiplication.
- 4. A display controller according to claim 1, wherein said second logical operation means includes means for selectively performing a logical operation based on second operation data applied thereto, further comprising fourth register means, coupled to said performing means, for storing said second operation data to determine a specific logical operation performed in said second logical operation, so that said second logical operation means effects said specific logical operation commanded by said second operation data.
- 5. A display controller according to claim 4, wherein said second logical operation is an exclusive-OR operation.
- 6. A display control as in claim 1, wherein said second pattern is displayed as a center part of said cursor.
Priority Claims (1)
Number |
Date |
Country |
Kind |
60-55128 |
Mar 1985 |
JPX |
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Parent Case Info
This is a continuation of application Ser. No. 841,093, filed Mar. 18, 1986, which was abandoned upon the filing hereof.
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Continuations (1)
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Number |
Date |
Country |
Parent |
841093 |
Mar 1986 |
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